Spies in the sky
- SPYING is a sophisticated and expensive businessâ€”and gathering military intelligence using unmanned aircraft can be prohibitively so. Predator and Global Hawk, two types of American drone frequently flown in Afghanistan and Iraq, cost around $5,000 and $26,500 an hour respectively to operate. The aircraft themselves cost between $4.5m and $35m each, and the remote-sensing equipment they carry can more than double the price. Which is why less elegant but far cheaper balloons are now being used instead.